It has long been recognized that an electronic data handling system should have some associated mechanism or method of operation for preserving the data separately from the system itself. In this way, the data are saved in case of a loss of power to, or an internal failure of, the system. In the case of large computer-based systems, data backup is provided by storing copies of the data separately from the system. These copies are updated frequently in order to minimize the effort that would be required to bring the data up to date in case of a failure.
Smaller computer systems, such as personal computers (PCs), can likewise benefit from data backup. Separate magnetic tape input/output devices, for example, are already used for backup purposes. Typically, however, a magnetic tape device is not used for routine input/output operations with a PC, and therefore represents an additional piece of equipment to be maintained with the computer system. Another limitation of conventional magnetic tape backup devices is their incompatibility with tape backup devices manufactured by others and even other tape backup devices of the same model. Thus, as a practical matter, backup data cannot be transferred from one magnetic tape device to another.
The optical disk is another device that is presently being developed, and that could be useful as a backup device. Recording optical disk units, however, presently represent a relatively expensive means of data backup.
Most modern PC systems, on the other hand, have at least one floppy disk drive for use as an input/output device. Floppy disks are generally used for storage of a few programs and/or data for those programs. Their use as a backup device, however, is relatively inefficient because floppy disks have relatively low data storage capability. For example, the two-sided data storage capacity of a 31/2-inch floppy disk is 720 kilobytes, whereas the date storage capability of built-in hard disk drives can exceed 40 megabytes. It would require at least 55 floppy disks to record all of the data that can be held on a 40 megabyte hard disk drive.
The present invention is directed toward a magnetic tape backup device that can transmit data with a disk drive head so that a magnetic tape can serve as a backup medium.